The invention presented herein relates to electrophotographic copy machines having an adjustable time exposure control circuit and, in particular, to such copy machines wherein the exposure control circuit automatically reduces the exposure time when the temperature within the copy machine increases.
Electrophotographic copy machines are available which use an intermediate sheet to which light from a light source is directed while the original to be copied is in face-to-face contact with the intermediate sheet. The original and intermediate sheet combination is placed on a platen. The platen, as well as the machine interior, increases in temperature when a number of copies are made in a short period of time. The intermediate sheet is temperature sensitive such that the exposure time required to obtain a copy of a given quality decreases with an increase in the temperature to which the intermediate sheet is subjected. In prior copiers of this type, the exposure time is manually selected so that a "dial chasing" problem is presented in the operation of such copiers due to changes in the temperature within the copy machine.